Someone recently told me that when he worked for the BLM, there was a lot of LDS folk, which reinforced my observation that they are overrepresented in federal jobs in general (I have no evidence for this, just several anecdotes). I assumed it is because they usually don't smoke marijuana, so they are more likely to be eligible. That abstract gave more compelling possibilities that I didn't think of, that don't seem conspiratorial, like the higher multilingual likelihood at concentrated places like BYU, making it a great spot for recruiting.
Does the article go into more detail on how they "corrupted" the FBI that is not easily explained by them simply being ideal FBI hires?